Desk top construction



Nov. 3, '1959 K. P. GRUBE 4 DESK TOP CONSTRUCTION Filed April 20, 1956 2Sheets-Sheet 1' 30 J2 ,zkz/eni'or 36 [fir-Z F 672656 B W (30 "1 17a Nov.3, 1959 K. P. GRUBE 2,911,274

DESK TOP CONSTRUCTION Filed April 20, 1956 2 Sheets-Sheet 2fizz/6272,5297 KarZ P Grue United States Patent ment Inc., a corporationof Illinois Application April 20, 1956, Serial No. 579,554 8 Claims.(Cl. 311-106) This invention relates to a desk top employing-a sandwichtype construction, and more particularly is concerned with the specificconstructional features and methods employed in providinga sandwicharrangement for use as a desk top in order to achieve uniform qualitydesk tops over a wide range-of. sizes and shapes.

In the prior art a wide variety of desk top arrangements are known, witheach arrangement emphasizing certain features of construction at thesacrifice of others. For example, such'tops', when'rnade of wood, haveordinarily been constructed in one piece or in laminar form, or, 'ifmade of metal, of hollow form employing internal spaced reinforcingmembers, and such designs emphasize one or more specific advantages,such as low cost, light weight, high strength, high rigidity, flatness,etc., while compromising other features not considered important2,911,274 Patented Nov. 3, 1959 Other objects and. advantages of theinvention will be apparent during the course of the followingdescription.

In the accompanyingdrawings forming a part of this specification and inwhich like numerals are employed t'oidesignate like parts throughout thesame.

Fig. 1 is a fragmentary perspective view of 'one corner of a desk andillustrates the desk top construction of this invention, the cornerportion of the desk top being broken away to more clearly illustrate'theform of the several elements comprising the desk top;

Fig. 2 is an enlarged exploded view of the corner portions of :theelements of the desk top;

Fig. 3-is an enlarged fragmentary sectional view illustratingrdetails ofthe desk top construction and is taken on the line 3-3 of Fig. 1;

I Fig. 4 is a plan view of a desk having an oversized and irregularlycontoured top;

I Fig. 5 is an enlarged fragmentary sectional view illustrating; thedetails of the desk top shown in Fig. 4 and is takenon the line 55 ofFig. 4;

Fig. 6 is a fragmentary perspective view of the formed angles employedinthe edge construction of Fig. 5; and

Fig. 7 is adetailed view similar to Fig. 5 but illustrating a modifiedform of edge construction.

Basically, the desk top consists of a filler 10 of cellular structurethat preferably resembles a honey combiand which may be formed fromkraftpaper impregnated with a. phenolic resin and rigidly bonded betweentwo flat to some given application. Thus; the desk art has "notdeveloped a universally applicable desk top construction.

Accordingly, it is the principal object of the invention to overcome thedeficiencies of the prior art arrangements and provide a single desktop. construction that exhibits a maximum strength to weight ratio; thatis of uniform cross sectional configurationjfthat is uniformly rigid;that provides a uniform and permanent flat upper surface; that isdurable, fire-resistant and pest resistant; and that lends itself ;tolow cost mass production techniques.

, Prior art desk tops involve a variety of different construction andproduction techniques whereasthe universal applicability, of theconstruction of the present invention to desk and table tops of variousexternal configurations allows standardized production 'techniqUes to beemployed. This possibility for standardization that is offered bythe'invention contributes,toujadditional, savings in manufacturing costsand mininiiz l theplantequipment required. 1 v

Gen'erally speaking, the sandwich construction forthe desktop of thisinvention consists of top and. bottom 1 metal plates or'p an s spacedapart bya filler composed of a cellular paper arrangement whichfin crosssection preferably' simulates a honey comb. Special'techr' iquesandmethods are employedto makenthis construction suitable to the productionof an economical high quality desk and great care is taken in bondingthe plates or pans to the "fillerlin order to achieve a permanent anduniform adhesion] In the case of desks of conventional shape, thev edgeconstruction and ornamentation may be applied according to conventionalpractices.- Howeveniinfthe case of desk tops of irregular shapes whichpresent difficult manufacturing problems as respects the edge:,construction, simplified constructions and methods have been developedthat .oiferin portaut pportunities for standardization andfitsaccompanying economy of manufacture. h form cross sectio1ialconfiguration is arranged for use with'blind fasteners of sturdyconstruction and superior holding power I i I ing structure.

sandwich co nstructiiinljemploying a ifiller of uniwhich secure the desktop to its s'upportsh pp ng.

- sheets or pans ,of steel. Of course, other types of honey comb orcellular structures may be used. The filler whether in one piece orseveral may be cut to shapeby a band saw or in any other convenient way.This impregnated paper type-of filler is moisture and fire resistant andis. .not.subject to deterioration.

The topv and bottom sheets are of any suitable sheet metal material, andpreferably of 22 gauge steel, and are designated 11 and 12,respectively. As indicated, a top covering 13 is bonded to the flatouter surface presented by top sheet 11. Any. conventional coveringmaterial may be employed for this top covering 13 and by way of aspecific example, linoleum or Textolite are frequently used. The edgesof the steel sheets are provided with vmarginal overlapping flanges, andare masked by a suitable decorative edging 14 which is fastenedin placeby suitable sheet nietalscrews'le' which, preferably, also'secure-theflanges together. T

This'basic'ar'rangement fulfills the requirements of all known ,desk topapplications. Invaddition, this single arrangement offers vastlysuperior physical characteristics and is capable vof replacing all ofthe many and varied desktop constructions presently employed. Theresultant standardization made possible by the present invention oifersimportant economies in the desk manufacturing art v Among the manyhighly advantageous physical characteristics thefact that the presentdesk top construction'exhibitsa substantially higher strength toweightratio than any of the priorart'airrangements. The desk top of theinventionis approximately sixteenv times.as rigid as" a, conventionalsteel desktop of the same weight. The weight of a honey comb sandwich.type desktop 6 O" x 30") is only 48 pounds whereas the weight of aconventional steel reinforced desk top of the same dimension is.about 60pounds. Furthermore, a honey comb conventi'onal.,,s'teel reinforced.topover the same span;

Not only areidesk. topsen bodying the light weight honey comb sandwich.type construction easier to I handle, Y but they also effect vaconsiderable savings in -freight and 'i, i V I Another feature whichrenders this construction pan ticularly effective inthe production ofdesk tops, is the fact that its cross section is everywhere uniform suchthat no special reinforcing problems arise in the production ofirregularly shaped tops. Similarly, all areas of the desk top areequally well adapted for attachment to the supporting pedestal. Thisuniform construction results in a highly desirable inherent rigidity forthe top structure which is so important in oversize desktops which havebecome increasingly popular in recent years. tion, this inherentrigidity prevents machines supported on the desk top from jumpng ormoving about on the top during operation, as so often happens withconventional steel reinforced tops.

Probably the most important single requirement of a desk top is that itbe flat and the honey comb sandwich type construction is particularlyeflicacious in achieving this goal. Apart from the obvious desirabilityof providing a flat writing surface, the absolute flatness of the honeycomb construction improves the bonding between the top covering 13 andthe upper surface of the top pan 11. In this connection it should benoted that the rigidity and flatness of the honey comb top renders thistop readily adaptable to the use of a squeeze roll press for applyingthe top covering material to the top pan. It has been observed thatconventional steel reinforced tops eventually develop waves or highspots directly over the reinforcing members, but this objectionablecharacteristic can never arise due to the more uniform supporting actionbuilt into the present arrangement.

The desk tops of the present invention are constructed according to thefollowing procedures:

A. Adhesive is applied to the contacting surfaces of the paper honeycomb and the top and bottom pans;

Preferably a roller coater is employed for applying adhesive to thehoney comb structure while the adhesive may be sprayed on to the metalpans.

The adhesive preferably employed is of the class called synthetic rubberadhesive (solvent). The adhesive consists of a mixture of neoprene andresin dissolved in a ketone solvent such as acetone, methyl ethylketone, etc. This combination produces high initial tack and strengthafter the solvent has been driven off. The resin then affords muchhigher strength upon aging while the neoprene lends the characteristicof toughness Without embrittlement.

B. In production of limited quantities these parts may then be hung upovernight to allow the adhesive to dry. However, the arrangement isreadily adapted to mass production techniques and in such an instance aninfra red drying oven is employed to reduce the adhesive drying time toa matter of minutes.

C. The principal parts of the desk top are then assembled, preferably,in inverted relationship. Thus, the requisite number of honey combpieces are properly located on top of the inner surface of the' top panand the bottom pan is then applied to complete the sandwich. Of course asingle appropriately contoured honey comb piece may be used if desired.

In addirectangular shape is shown, it will be seen that the top andbottom steel pans may be formed from steel sheets of appropriate shape.The straight sided sheet metal pans are formed with arcuate cutouts 20at their corners. In forming the rounded corners on the top and bottompans, the straight sides are first bent down to form right angle flangesand then suitable drawing dies are employed to form the arcuate cornerflanges 21. The flange portions 22 of the top pan are formed with a ribor bead 23 so that when the parts are asesmbled, the flange portions ofthe top pan nest within the flange portions 24 of the bottom pan withthe upper edges of the bottom flanges closelyadjacent to the bead 23(see Fig. 3).

The manner of arranging and forming the flanges has only been brieflydescribed herein but is generally similar to that shown and described inUnited States Patent No. 2,646,327 to F. A. Saaf.

After the sandwich has been completely assembled, as described, with theparts bonded together and a top covering of linoleum or other suitablematerial applied, the edge molding 14 is secured to the flanges. Forthis purpose the flange portions are formed with registering apertures26 at spaced points about the periphery of the desk top and the moldingis secured through these apertures.

The molding consists of a channel shaped retaining member 27 whichpreferably is a flexible strip of extruded aluminum adapted for mountingand retaining an ornamental covering strip 28 which may be of extrudedor molded pliant material such as a vinyl plastic. The screws 15 engagein the apertures 26 to fasten the retaining member 27 to the overlappingflanges 22 and 24, and then the ornamental strip 28 is fitted into placeand it serves to mask the fastening screws.

The present invention employs a highly effective arrangement forattaching the desk top to the supporting structure 30 as shown in Fig. 3wherein a headed fastener 31 is inserted in a countersunk opening 32 inthe bottom pan and is mounted with its head 33 in flush relation withthe bottom pan 12. These punched and embossed openings 32 for thefasteners 31 are formed when the pan is flat. The fastener 31 is appliedto the desk top assembly by a special tool (not shown) which exertscompression between the head 33 and a threaded bore 34 D. In theproduction of limited quantities of desk tops the assemblage is heatedin a steam heated hydraulic platen press for approximately five minutes.In a mass production arrangement, this operation may be accomplished bymeans of an infra red oven for heating andla squeeze pressure rollmachine for bondin'g'the parts together under pressure.

B. After the bonding operation the tops. are stacked on a flat surfaceand suitably covered'for assuring uniform cooling. After they have beencooled, they are ready for the final assembly operations of applying thetop covering which as previously pointed out may also be accomplishedbymeans of a squeeze roll press and finally the edging is securedto theassembled top.

Depending upon the configuration of the desk top,

slightly different edge constructions are employed, Re-

ferring now to Figs. 1-3, wherein .a desk top. of generally 'to desktops of conventional shape.

structure.

formed in the fastener to upset the shank of the fastener and form aretaining shoulder 35. Thus the bottom pan 12 is gripped between thehead 33 and shoulder 35 of the fastener. The threaded bore 34subsequently receives anattaching screw 36 that is passed through thesupporting structure 30 and held therein by a suitable washer 37. Whilethe specific fastener shown herein is not new per se, its use in thedisclosed manner in connection with the desk top construction of thepresent invention offers unique advantages. It will be apparent that thehoney comb structure yields as required in response to the concentratedforces developed in the region of the countersunk openings, withoutinterfering with the firm bonding of the filler 10 to the top and bottompans 11 and 12.

The arrangement allows a blind fastener to be connected with equalfacility at any desired point on the bottom pan and this is aparticularly important factor in the case of desks having tops ofunusual configuration. When spaced reinforcing members of the prior artare employed in a desk top construction, care must be given to theirlocation in order to insure that the desk top may be attached to thesupporting structure in proper relationship.

The flanged edge construction of Figs. 1 3 is well suited However,attractively contoured desk top configurations, such as shown 'at 38 inFig. 4,'involving a continuously curving edge surface have becomeincreasingly popular and the problem of economically producing suchconfigurations is for the first time achieved by means of the honey combIn addition, the honey comb sandwich type arrangement due to its uniformrigidity and high strength permits such arrangements to overhang thesupporting structure by appreciable amounts without fear of damage whenthe overhanging portion is used to support people or office machines.The basic arrangement and construction of the sandwich is similar to;that outlined'hereinbefore, however, special techniques areemployedfo'rthe edge construction.

A preferred form of edge construction is shown in Fig. 5 wherein it willbe seen that the top and bottom members 11a and 12a, respectively, areperfectly fiat and have no integral depending flanges. Thus, theymayreadily be die cut into any desired shape or size. 'In order to providea curved edge construction, formed angles are preferably spot welded tothe top and bottom sheets. As indicated in Fig. 6, the horizontallydisposed flanges 40 and 41 of these angles are formed with a pluralityof notches 42 in order to permit the angle to be bent to any desiredcurved shape. After forming, these horizontal flanges are then securedto the marginal edges of the top and bottom sheets as indicated in Fig.5. Again the arrangement is such that the top sheet with its-ledgeflanges nests within the edge flanges of the bottom sheet and theflanges are formed .with. registering apertures, either before or afterwelding, that'receive the mounting screws 15 for the retaining strip. I

It will be apparent that this construction is applicable to desk tops ofany desired contour. Here again, a headed blind fastener 31 having anupsettable portion forming a gripping shoulder 35 is employed forattaching the top to its supporting structure 30.

In lieu of employing continuous angles, a plurality of appropriatelyspaced individual brackets may be secured about the periphery of thesheet metal members 11a and 12a to receive the edge molding. In thisconnection, it should be noted that it is not impractical toprovide'only one of the pans with depending flanges for mounting theedge molding since the adhesive together with the edge construction canbe depended upon" to maintain the sandwich unitary.

An alternative arrangement for providing edges on curved desk tops isillustrated in Fig. 7 wherein the top and bottom pans 11b and 12b areshown as including integral rolled over flange portions 44 and 45,respectively. Angle edging machines for this purpose are well known inthe art and are readily able to form right angle flanges on plateshaving curved marginal areas. One such hand operated angle edger isknown as Model F produced by the Maplewood Manufacturing Company ofChicago, Illinois.

In the construction of Fig. 7 the top and bottom sheets are flangedprior to the assembly of the sandwich and, also priorto their assembly,a continuous flexible strip 46 is inserted between the marginal edges ofthe top and bottom flanges. This strip is of a greater height than thevertical spacing between the opposed flanges and'as the molding strip 27is applied suitableholes are drilled through the strips 27 and 46 toreceive self tapping screws 15 to holdthemolding or retaining strip 27in place.

Thus it will be seen that the objects of the invention have beenaccomplished in that the standardized honey comb filler structureprovides high strength, light weight, economical desk tops regardless ofthe configuration desired. In addition, the tops may readily be providedwith a decorative edging and they accommodate sturdy fasteners forfacilitating their attachment to the supporting structure, as shown inFig. 4.

g'inal flange, a composite cellular filler structure interposed betweensaid pans with bonding material securing the filler structure to thepans, a layer of desk top material overlying the exterior of the upperone of said pans with bonding material adhering substantially the entireexpanse of said layerto said upper pan, and a flexible molding overlyingand masking themar'ginal flange and including attachment means engagingsaid flange to secure said flexible molding in place. I i

V 2. In combination, a supporting structure including a substantiallyflat surface having spaced openings, a desk top including top and bottomflat sheet metal pans and an interposed compositecellular fillerstructure secured thereto by bonding material, a layer of desk topmaterial overlying the exterior of said upper pan with bonding materialadhering substantially the entire expanse of said layer to said upperpan, said bottom metal .pan having spaced inwardly embossed portionsformed with openings arranged for registration with the openings in saidflat plate, said filler structure being yieldable in response to thelocalized pressures in the region of said embossed portions,mounting'fasteners disposed in the openings in the bottom panand eachincluding a head and deformable shoulde'r'means gripping the embossedportions surrounding the openings in the bottom pan with the head lyingflushwith the outer surface of:the bottom pan, said fasteners havingthreaded bores, and threaded attachment means passing through theopenings in the flat surface "of said supporting structure and saidbottom pan and engaged between said flat surface and the threaded boresof said fasteners to secure the desk top to the supporting structure.

3. A desk top comprising a pair of flat sheet metal pans "and aninterposed composite cellular filler structure secured thereto bybonding material, each pan including inturned marginal flanges arrangedin overlapping nesting relationship and formed with registeringopenings, a layer of desk top material overlying the exteriorof theupper oneof said pans with bonding material adhering substantially theentire expanse of said layer to said upper pan, and a flexible moldingoverlying and masking the marginal flanges and including attachmentmeans engaging the openings in said flanges to secure said flexiblemolding in place.

4. A desk top comprising a pair of flat sheet metal pans, each includinginturned marginal flanges, a composite cellular filler structure and asurrounding attachment strip interposed between said pans and spacingsaid flanges apart a distance less than the width of the attachmentstrip, bonding material securing said filler structure to said pans, alayer of desk top material overlying the exterior of the upper one ofsaid pans with bonding ma- It should be understood that the descriptionof illus- I trative forms of the invention are for the purpose ofcomplying with Section 112, Title 35 of the United States Code and thatthe appended claims should beconstrued as broadly as the prior art willpermit.

I claim: I

1. A desk top comprising a pair of. flat sheet. metal pans, at least oneof said pans includingan inturned marterial adhering substantially theentire expanse of said layer to said upper pan, and a flexible moldingoverlying and masking the marginal flanges and attachment strip andincluding attachment means engaging said strip such that said stripabuts against said flanges and holds said flexible molding in place. i

5. A desk top comprising a pair of sheet metal pans each includinginturned marginal flanges, a reinforcing structure and a surroundingstrip interposed between said pans'and spacing said pans apart adistance less than the width of the attachment strip, means for securingsaid reinforcing structure to said pans, and a flexible moldingoverlying and masking the marginal flanges and attachment strip andincluding attachment means passing between said flanges and engagingsaid strip such that said strip abuts against said flanges and holdssaid flexible molding in-place.

6. A contoureddesk top of irregular shape comprising a pair of fiatsheet metal pans and an interposed composite cellular structure securedthereto by bonding material, a layer of desk top material overlying theexterior of the upper one of said pans with bonding material ad- 7 saidupper pan, each pan having inturned marginal flanges comprising formedangles secured to the pans proper and arrangedin overlapping nestingrelationship, said overlapping flanges having registering openings, and

a flexible molding overlying and masking the flanges and includingattachment means engaging the openings in said flanges to secure saidflexible molding in place.

7. The method of constructing a desk top of any desired contour whichcomprises forming top and bottom metal plates of the desired contour,providing laterally extending marginal flange means on at least one ofsaid plates, shaping a composite cellular filler structure substantiallycoextensive with said plates to the desired contour, bonding the top andbottom plates to the filler structure to provide a desk top having auniform cross sectional construction of the desired contour, shaping alayer of desk top material substantially coextensive with the upperplate, bonding substantially the entire expanse of said layer to theexterior of said upper plate, and securing a flexible edging at spacedpoints to the marginal flange means to mask'the same.

8. The method of construcing a desk top of any desired contour whichcomprises forming top and bottom metal pans of the desired contour andinwardly embossing and aperturing the bottom pan at spaced points,providing inwardly extending marginalflange means on at least one ofsaid pans, shaping acomposite cellular filler structure substantiallycoextensive with said pans to the desired contour, pressure bonding thetop and bottom pans to the filler structure such that the filler yieldsin response to the localized pressures'in the region of the embossedpoints and said pans are disposed'inparallel relation, attaching headedfasteners to said embossed portions with the heads thereof inflush'relation with said bottom pan, shaping a layer of desk topmaterial substantially coextensive with the upper pan, pressure bondingsubstantially the entire expanse of said layer to the exterior of saidupper pan,and securing a flexible edging at spaced points to themarginal flange means to mask the same.

References Cited in the file of this patent UNITED STATES PATENTS1,779,426 Frederick Oct. 26, 1930 1,873,932 Hunter." Aug. 23, 19321,876,330 Loetscher Sept. 6, 1932 2,269,331 Arborn Ian. 6, 19422,461,823v Jones Feb. 15, 1949 2,477,852. Bacon Aug. 2, 1949 2,479,342Gibbons Aug. 16,1949 2,609,068' Pajak Sept. 2, 1952 2,646,327 Saaf July21, 1953 2,739,640 Brinker March 27, 1956 UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent No. 2,911,274 November 3, 1959 Karl P.Grube It is hereby certified that error appears in the printedspecification of the above numbered patent requiring correct-ion andthat the said Letters Patent should readas corrected below.

Column 6, 1111620, for "plate" read surface column '7, line" 22, for"construcing" read constructing Signed and sealed this 26th day of April1960.

(SEAL) Attest:

KARL H. AXLINET Attesting ()flicer ROBERT C. WATSON Commissioner ofPatents

